cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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ad7291.c (13442B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * AD7291 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor
      4 *
      5 * Copyright 2010-2011 Analog Devices Inc.
      6 */
      7
      8#include <linux/device.h>
      9#include <linux/err.h>
     10#include <linux/i2c.h>
     11#include <linux/interrupt.h>
     12#include <linux/kernel.h>
     13#include <linux/module.h>
     14#include <linux/mutex.h>
     15#include <linux/regulator/consumer.h>
     16#include <linux/slab.h>
     17#include <linux/sysfs.h>
     18
     19#include <linux/iio/iio.h>
     20#include <linux/iio/sysfs.h>
     21#include <linux/iio/events.h>
     22
     23/*
     24 * Simplified handling
     25 *
     26 * If no events enabled - single polled channel read
     27 * If event enabled direct reads disable unless channel
     28 * is in the read mask.
     29 *
     30 * The noise-delayed bit as per datasheet suggestion is always enabled.
     31 */
     32
     33/*
     34 * AD7291 registers definition
     35 */
     36#define AD7291_COMMAND			0x00
     37#define AD7291_VOLTAGE			0x01
     38#define AD7291_T_SENSE			0x02
     39#define AD7291_T_AVERAGE		0x03
     40#define AD7291_DATA_HIGH(x)		((x) * 3 + 0x4)
     41#define AD7291_DATA_LOW(x)		((x) * 3 + 0x5)
     42#define AD7291_HYST(x)			((x) * 3 + 0x6)
     43#define AD7291_VOLTAGE_ALERT_STATUS	0x1F
     44#define AD7291_T_ALERT_STATUS		0x20
     45
     46#define AD7291_BITS			12
     47#define AD7291_VOLTAGE_LIMIT_COUNT	8
     48
     49
     50/*
     51 * AD7291 command
     52 */
     53#define AD7291_AUTOCYCLE		BIT(0)
     54#define AD7291_RESET			BIT(1)
     55#define AD7291_ALERT_CLEAR		BIT(2)
     56#define AD7291_ALERT_POLARITY		BIT(3)
     57#define AD7291_EXT_REF			BIT(4)
     58#define AD7291_NOISE_DELAY		BIT(5)
     59#define AD7291_T_SENSE_MASK		BIT(7)
     60#define AD7291_VOLTAGE_MASK		GENMASK(15, 8)
     61#define AD7291_VOLTAGE_OFFSET		8
     62
     63/*
     64 * AD7291 value masks
     65 */
     66#define AD7291_VALUE_MASK		GENMASK(11, 0)
     67
     68/*
     69 * AD7291 alert register bits
     70 */
     71#define AD7291_T_LOW			BIT(0)
     72#define AD7291_T_HIGH			BIT(1)
     73#define AD7291_T_AVG_LOW		BIT(2)
     74#define AD7291_T_AVG_HIGH		BIT(3)
     75#define AD7291_V_LOW(x)			BIT((x) * 2)
     76#define AD7291_V_HIGH(x)		BIT((x) * 2 + 1)
     77
     78
     79struct ad7291_chip_info {
     80	struct i2c_client	*client;
     81	struct regulator	*reg;
     82	u16			command;
     83	u16			c_mask;	/* Active voltage channels for events */
     84	struct mutex		state_lock;
     85};
     86
     87static int ad7291_i2c_read(struct ad7291_chip_info *chip, u8 reg, u16 *data)
     88{
     89	struct i2c_client *client = chip->client;
     90	int ret = 0;
     91
     92	ret = i2c_smbus_read_word_swapped(client, reg);
     93	if (ret < 0) {
     94		dev_err(&client->dev, "I2C read error\n");
     95		return ret;
     96	}
     97
     98	*data = ret;
     99
    100	return 0;
    101}
    102
    103static int ad7291_i2c_write(struct ad7291_chip_info *chip, u8 reg, u16 data)
    104{
    105	return i2c_smbus_write_word_swapped(chip->client, reg, data);
    106}
    107
    108static irqreturn_t ad7291_event_handler(int irq, void *private)
    109{
    110	struct iio_dev *indio_dev = private;
    111	struct ad7291_chip_info *chip = iio_priv(private);
    112	u16 t_status, v_status;
    113	u16 command;
    114	int i;
    115	s64 timestamp = iio_get_time_ns(indio_dev);
    116
    117	if (ad7291_i2c_read(chip, AD7291_T_ALERT_STATUS, &t_status))
    118		return IRQ_HANDLED;
    119
    120	if (ad7291_i2c_read(chip, AD7291_VOLTAGE_ALERT_STATUS, &v_status))
    121		return IRQ_HANDLED;
    122
    123	if (!(t_status || v_status))
    124		return IRQ_HANDLED;
    125
    126	command = chip->command | AD7291_ALERT_CLEAR;
    127	ad7291_i2c_write(chip, AD7291_COMMAND, command);
    128
    129	command = chip->command & ~AD7291_ALERT_CLEAR;
    130	ad7291_i2c_write(chip, AD7291_COMMAND, command);
    131
    132	/* For now treat t_sense and t_sense_average the same */
    133	if ((t_status & AD7291_T_LOW) || (t_status & AD7291_T_AVG_LOW))
    134		iio_push_event(indio_dev,
    135			       IIO_UNMOD_EVENT_CODE(IIO_TEMP,
    136						    0,
    137						    IIO_EV_TYPE_THRESH,
    138						    IIO_EV_DIR_FALLING),
    139			       timestamp);
    140	if ((t_status & AD7291_T_HIGH) || (t_status & AD7291_T_AVG_HIGH))
    141		iio_push_event(indio_dev,
    142			       IIO_UNMOD_EVENT_CODE(IIO_TEMP,
    143						    0,
    144						    IIO_EV_TYPE_THRESH,
    145						    IIO_EV_DIR_RISING),
    146			       timestamp);
    147
    148	for (i = 0; i < AD7291_VOLTAGE_LIMIT_COUNT; i++) {
    149		if (v_status & AD7291_V_LOW(i))
    150			iio_push_event(indio_dev,
    151				       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
    152							    i,
    153							    IIO_EV_TYPE_THRESH,
    154							    IIO_EV_DIR_FALLING),
    155				       timestamp);
    156		if (v_status & AD7291_V_HIGH(i))
    157			iio_push_event(indio_dev,
    158				       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
    159							    i,
    160							    IIO_EV_TYPE_THRESH,
    161							    IIO_EV_DIR_RISING),
    162				       timestamp);
    163	}
    164
    165	return IRQ_HANDLED;
    166}
    167
    168static unsigned int ad7291_threshold_reg(const struct iio_chan_spec *chan,
    169					 enum iio_event_direction dir,
    170					 enum iio_event_info info)
    171{
    172	unsigned int offset;
    173
    174	switch (chan->type) {
    175	case IIO_VOLTAGE:
    176		offset = chan->channel;
    177		break;
    178	case IIO_TEMP:
    179		offset = AD7291_VOLTAGE_OFFSET;
    180		break;
    181	default:
    182	    return 0;
    183	}
    184
    185	switch (info) {
    186	case IIO_EV_INFO_VALUE:
    187		if (dir == IIO_EV_DIR_FALLING)
    188			return AD7291_DATA_HIGH(offset);
    189		else
    190			return AD7291_DATA_LOW(offset);
    191	case IIO_EV_INFO_HYSTERESIS:
    192		return AD7291_HYST(offset);
    193	default:
    194		break;
    195	}
    196	return 0;
    197}
    198
    199static int ad7291_read_event_value(struct iio_dev *indio_dev,
    200				   const struct iio_chan_spec *chan,
    201				   enum iio_event_type type,
    202				   enum iio_event_direction dir,
    203				   enum iio_event_info info,
    204				   int *val, int *val2)
    205{
    206	struct ad7291_chip_info *chip = iio_priv(indio_dev);
    207	int ret;
    208	u16 uval;
    209
    210	ret = ad7291_i2c_read(chip, ad7291_threshold_reg(chan, dir, info),
    211			      &uval);
    212	if (ret < 0)
    213		return ret;
    214
    215	if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE)
    216		*val = uval & AD7291_VALUE_MASK;
    217
    218	else
    219		*val = sign_extend32(uval, 11);
    220
    221	return IIO_VAL_INT;
    222}
    223
    224static int ad7291_write_event_value(struct iio_dev *indio_dev,
    225				    const struct iio_chan_spec *chan,
    226				    enum iio_event_type type,
    227				    enum iio_event_direction dir,
    228				    enum iio_event_info info,
    229				    int val, int val2)
    230{
    231	struct ad7291_chip_info *chip = iio_priv(indio_dev);
    232
    233	if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE) {
    234		if (val > AD7291_VALUE_MASK || val < 0)
    235			return -EINVAL;
    236	} else {
    237		if (val > 2047 || val < -2048)
    238			return -EINVAL;
    239	}
    240
    241	return ad7291_i2c_write(chip, ad7291_threshold_reg(chan, dir, info),
    242				val);
    243}
    244
    245static int ad7291_read_event_config(struct iio_dev *indio_dev,
    246				    const struct iio_chan_spec *chan,
    247				    enum iio_event_type type,
    248				    enum iio_event_direction dir)
    249{
    250	struct ad7291_chip_info *chip = iio_priv(indio_dev);
    251	/*
    252	 * To be enabled the channel must simply be on. If any are enabled
    253	 * we are in continuous sampling mode
    254	 */
    255
    256	switch (chan->type) {
    257	case IIO_VOLTAGE:
    258		return !!(chip->c_mask & BIT(15 - chan->channel));
    259	case IIO_TEMP:
    260		/* always on */
    261		return 1;
    262	default:
    263		return -EINVAL;
    264	}
    265
    266}
    267
    268static int ad7291_write_event_config(struct iio_dev *indio_dev,
    269				     const struct iio_chan_spec *chan,
    270				     enum iio_event_type type,
    271				     enum iio_event_direction dir,
    272				     int state)
    273{
    274	int ret = 0;
    275	struct ad7291_chip_info *chip = iio_priv(indio_dev);
    276	unsigned int mask;
    277	u16 regval;
    278
    279	mutex_lock(&chip->state_lock);
    280	regval = chip->command;
    281	/*
    282	 * To be enabled the channel must simply be on. If any are enabled
    283	 * use continuous sampling mode.
    284	 * Possible to disable temp as well but that makes single read tricky.
    285	 */
    286
    287	mask = BIT(15 - chan->channel);
    288
    289	switch (chan->type) {
    290	case IIO_VOLTAGE:
    291		if ((!state) && (chip->c_mask & mask))
    292			chip->c_mask &= ~mask;
    293		else if (state && (!(chip->c_mask & mask)))
    294			chip->c_mask |= mask;
    295		else
    296			break;
    297
    298		regval &= ~AD7291_AUTOCYCLE;
    299		regval |= chip->c_mask;
    300		if (chip->c_mask) /* Enable autocycle? */
    301			regval |= AD7291_AUTOCYCLE;
    302
    303		ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
    304		if (ret < 0)
    305			goto error_ret;
    306
    307		chip->command = regval;
    308		break;
    309	default:
    310		ret = -EINVAL;
    311	}
    312
    313error_ret:
    314	mutex_unlock(&chip->state_lock);
    315	return ret;
    316}
    317
    318static int ad7291_read_raw(struct iio_dev *indio_dev,
    319			   struct iio_chan_spec const *chan,
    320			   int *val,
    321			   int *val2,
    322			   long mask)
    323{
    324	int ret;
    325	struct ad7291_chip_info *chip = iio_priv(indio_dev);
    326	u16 regval;
    327
    328	switch (mask) {
    329	case IIO_CHAN_INFO_RAW:
    330		switch (chan->type) {
    331		case IIO_VOLTAGE:
    332			mutex_lock(&chip->state_lock);
    333			/* If in autocycle mode drop through */
    334			if (chip->command & AD7291_AUTOCYCLE) {
    335				mutex_unlock(&chip->state_lock);
    336				return -EBUSY;
    337			}
    338			/* Enable this channel alone */
    339			regval = chip->command & (~AD7291_VOLTAGE_MASK);
    340			regval |= BIT(15 - chan->channel);
    341			ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
    342			if (ret < 0) {
    343				mutex_unlock(&chip->state_lock);
    344				return ret;
    345			}
    346			/* Read voltage */
    347			ret = i2c_smbus_read_word_swapped(chip->client,
    348							  AD7291_VOLTAGE);
    349			if (ret < 0) {
    350				mutex_unlock(&chip->state_lock);
    351				return ret;
    352			}
    353			*val = ret & AD7291_VALUE_MASK;
    354			mutex_unlock(&chip->state_lock);
    355			return IIO_VAL_INT;
    356		case IIO_TEMP:
    357			/* Assumes tsense bit of command register always set */
    358			ret = i2c_smbus_read_word_swapped(chip->client,
    359							  AD7291_T_SENSE);
    360			if (ret < 0)
    361				return ret;
    362			*val = sign_extend32(ret, 11);
    363			return IIO_VAL_INT;
    364		default:
    365			return -EINVAL;
    366		}
    367	case IIO_CHAN_INFO_AVERAGE_RAW:
    368		ret = i2c_smbus_read_word_swapped(chip->client,
    369						  AD7291_T_AVERAGE);
    370			if (ret < 0)
    371				return ret;
    372			*val = sign_extend32(ret, 11);
    373			return IIO_VAL_INT;
    374	case IIO_CHAN_INFO_SCALE:
    375		switch (chan->type) {
    376		case IIO_VOLTAGE:
    377			if (chip->reg) {
    378				int vref;
    379
    380				vref = regulator_get_voltage(chip->reg);
    381				if (vref < 0)
    382					return vref;
    383				*val = vref / 1000;
    384			} else {
    385				*val = 2500;
    386			}
    387			*val2 = AD7291_BITS;
    388			return IIO_VAL_FRACTIONAL_LOG2;
    389		case IIO_TEMP:
    390			/*
    391			 * One LSB of the ADC corresponds to 0.25 deg C.
    392			 * The temperature reading is in 12-bit twos
    393			 * complement format
    394			 */
    395			*val = 250;
    396			return IIO_VAL_INT;
    397		default:
    398			return -EINVAL;
    399		}
    400	default:
    401		return -EINVAL;
    402	}
    403}
    404
    405static const struct iio_event_spec ad7291_events[] = {
    406	{
    407		.type = IIO_EV_TYPE_THRESH,
    408		.dir = IIO_EV_DIR_RISING,
    409		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
    410			BIT(IIO_EV_INFO_ENABLE),
    411	}, {
    412		.type = IIO_EV_TYPE_THRESH,
    413		.dir = IIO_EV_DIR_FALLING,
    414		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
    415			BIT(IIO_EV_INFO_ENABLE),
    416	}, {
    417		.type = IIO_EV_TYPE_THRESH,
    418		.dir = IIO_EV_DIR_EITHER,
    419		.mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
    420	},
    421};
    422
    423#define AD7291_VOLTAGE_CHAN(_chan)					\
    424{									\
    425	.type = IIO_VOLTAGE,						\
    426	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
    427	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),		\
    428	.indexed = 1,							\
    429	.channel = _chan,						\
    430	.event_spec = ad7291_events,					\
    431	.num_event_specs = ARRAY_SIZE(ad7291_events),			\
    432}
    433
    434static const struct iio_chan_spec ad7291_channels[] = {
    435	AD7291_VOLTAGE_CHAN(0),
    436	AD7291_VOLTAGE_CHAN(1),
    437	AD7291_VOLTAGE_CHAN(2),
    438	AD7291_VOLTAGE_CHAN(3),
    439	AD7291_VOLTAGE_CHAN(4),
    440	AD7291_VOLTAGE_CHAN(5),
    441	AD7291_VOLTAGE_CHAN(6),
    442	AD7291_VOLTAGE_CHAN(7),
    443	{
    444		.type = IIO_TEMP,
    445		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
    446				BIT(IIO_CHAN_INFO_AVERAGE_RAW) |
    447				BIT(IIO_CHAN_INFO_SCALE),
    448		.indexed = 1,
    449		.channel = 0,
    450		.event_spec = ad7291_events,
    451		.num_event_specs = ARRAY_SIZE(ad7291_events),
    452	}
    453};
    454
    455static const struct iio_info ad7291_info = {
    456	.read_raw = &ad7291_read_raw,
    457	.read_event_config = &ad7291_read_event_config,
    458	.write_event_config = &ad7291_write_event_config,
    459	.read_event_value = &ad7291_read_event_value,
    460	.write_event_value = &ad7291_write_event_value,
    461};
    462
    463static void ad7291_reg_disable(void *reg)
    464{
    465	regulator_disable(reg);
    466}
    467
    468static int ad7291_probe(struct i2c_client *client,
    469			const struct i2c_device_id *id)
    470{
    471	struct ad7291_chip_info *chip;
    472	struct iio_dev *indio_dev;
    473	int ret;
    474
    475	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
    476	if (!indio_dev)
    477		return -ENOMEM;
    478	chip = iio_priv(indio_dev);
    479
    480	mutex_init(&chip->state_lock);
    481
    482	chip->client = client;
    483
    484	chip->command = AD7291_NOISE_DELAY |
    485			AD7291_T_SENSE_MASK | /* Tsense always enabled */
    486			AD7291_ALERT_POLARITY; /* set irq polarity low level */
    487
    488	chip->reg = devm_regulator_get_optional(&client->dev, "vref");
    489	if (IS_ERR(chip->reg)) {
    490		if (PTR_ERR(chip->reg) != -ENODEV)
    491			return PTR_ERR(chip->reg);
    492
    493		chip->reg = NULL;
    494	}
    495
    496	if (chip->reg) {
    497		ret = regulator_enable(chip->reg);
    498		if (ret)
    499			return ret;
    500
    501		ret = devm_add_action_or_reset(&client->dev, ad7291_reg_disable,
    502					       chip->reg);
    503		if (ret)
    504			return ret;
    505
    506		chip->command |= AD7291_EXT_REF;
    507	}
    508
    509	indio_dev->name = id->name;
    510	indio_dev->channels = ad7291_channels;
    511	indio_dev->num_channels = ARRAY_SIZE(ad7291_channels);
    512
    513	indio_dev->info = &ad7291_info;
    514	indio_dev->modes = INDIO_DIRECT_MODE;
    515
    516	ret = ad7291_i2c_write(chip, AD7291_COMMAND, AD7291_RESET);
    517	if (ret)
    518		return -EIO;
    519
    520	ret = ad7291_i2c_write(chip, AD7291_COMMAND, chip->command);
    521	if (ret)
    522		return -EIO;
    523
    524	if (client->irq > 0) {
    525		ret = devm_request_threaded_irq(&client->dev, client->irq,
    526						NULL,
    527						&ad7291_event_handler,
    528						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
    529						id->name,
    530						indio_dev);
    531		if (ret)
    532			return ret;
    533	}
    534
    535	return devm_iio_device_register(&client->dev, indio_dev);
    536}
    537
    538static const struct i2c_device_id ad7291_id[] = {
    539	{ "ad7291", 0 },
    540	{}
    541};
    542
    543MODULE_DEVICE_TABLE(i2c, ad7291_id);
    544
    545static const struct of_device_id ad7291_of_match[] = {
    546	{ .compatible = "adi,ad7291" },
    547	{}
    548};
    549MODULE_DEVICE_TABLE(of, ad7291_of_match);
    550
    551static struct i2c_driver ad7291_driver = {
    552	.driver = {
    553		.name = KBUILD_MODNAME,
    554		.of_match_table = ad7291_of_match,
    555	},
    556	.probe = ad7291_probe,
    557	.id_table = ad7291_id,
    558};
    559module_i2c_driver(ad7291_driver);
    560
    561MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
    562MODULE_DESCRIPTION("Analog Devices AD7291 ADC driver");
    563MODULE_LICENSE("GPL v2");